21–30 of 197 posts
The same GPS the US Government reserves the right to reduce the precision when they feel like it? Seems risky idea to assume they will never do this.
I would hope aircraft would have multiband receivers that also support GLONASS, Galileo, and BeiDou. There's also Japan's QZSS and the regional Indian IRNSS.
How long until radar becomes an afterthought, and we get an issue because a transponder has failed?
I took flight school a few years ago, and had to learn to tune in non-directional radio beacons, and use VHF Omni-Directional Range tools for navigation. I wasn't allowed to use the GPS until I demonstrated mastery of the others. Considering that, I suspect the aviation industry will keep both systems working for a surprisingly long time.
If GPS were to become the sole way to do the latter, every airplane would effectively get an invisibility cloak that those who want to do evil can activate (and even worse. Switching off the on-board transmitter is less scary than spoofing signals)
Because of that, I would expect they keep using some way to detect planes that don’t tell them where they are, or radios broadcasting “plane P is at X,Y,Z” without a plane being there.
The same GPS the US Government reserves the right to reduce the precision when they feel like it? Seems risky idea to assume they will never do this.
Isn't low precision something like +/- 15 feet? For ATC, that seems more than good enough when they keep jets a mile+ apart. It just needs to be more precise than radar.
But if SA was enabled:
Before it was turned off on May 2, 2000, typical SA errors were about 50 m (164 ft) horizontally and about 100 m (328 ft) vertically
https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...
To an extent, this sounds terrifying. The first thing that jumped to my mind is that GPS be jammed or spoofed. In fact, the U.S. military in its shift away from COIN to great power competition in possibly highly contested environments is training to have less reliance on GPS: https://www.zerohedge.com/news/2018-01-26/usaf-begins-massiv... Radar can be jammed too, but I would guess the EM signature powerful enough to…
We still maintain Loran C[0]. Interesting to note receivers have been developed to grab the radio signal from all available stations, up to 40, and triangulate location with eLoran. It's a nice to have as backup to GPS however I'm not sure if it is effective against jamming or spoofing. So, the navy still teaches celestial navigation to officers. [1] EDIT: Apparently Loran C was discontinued in 2010. [0] https://en.w…
What does "still maintain" mean in this context? My Loran-C receiver stopped working years ago when we turned off the signals.
https://en.wikipedia.org/wiki/Loran-C#Loran-C_in_the_21st_ce...
How long until radar becomes an afterthought, and we get an issue because a transponder has failed?
Existing non-ADS-B based traffic management requires accurate altimeters and working transponders; we have always been at the mercy of systems that can fail. One of the many reasons for the substantial training of pilots.
To an extent, this sounds terrifying. The first thing that jumped to my mind is that GPS be jammed or spoofed. In fact, the U.S. military in its shift away from COIN to great power competition in possibly highly contested environments is training to have less reliance on GPS: https://www.zerohedge.com/news/2018-01-26/usaf-begins-massiv... Radar can be jammed too, but I would guess the EM signature powerful enough to…
Radar has been jammed in the past by accident , since home routers now operate on the same band. See https://arstechnica.com/information-technology/2015/09/fcc-a... . 5G coming in doesn't improve matters. GPS is actually reserved, so there's going to be a lot less accidental interference.
that's only a plus if you're not expecting malicious interference. how much harder is radar to spoof compared to GPS?
Earlier quoted context omitted.
I’d feel a lot more comfortable if they retained RADAR as a backup - why not have both?
I can’t read the article (paywalled), but I would expect primary radar isn’t going anywhere around airports. We still have it, and our commercial planes have been required to have ADS-B transponders here for more than a decade. This is just for en-route tracking.